Matthews, T.J., Rigal, F., Triantis, K.A. & Wittaker, R.J. (2019) A global model of island species-area relationships.PNAS - Proceedings of The National Academy of Sciences of The United States of America, 116 (25), 12337-12342. DOI:10.1073/pnas.1818190116 (IF2019 9,412; Q1 Multidisciplinary Sciences)
The increase in species richness with island area (ISAR) is a well-established global pattern, commonly described by the power model, the parameters of which are hypothesized to vary with system isolation and to be indicative of ecological process regimes. We tested a structural equation model of ISAR parameter variation as a function of taxon, isolation, and archipelago configuration, using a globally distributed dataset of 151 ISARs encompassing a range of taxa and archipelago types. The resulting models revealed a negative relationship between ISAR intercept and slope as a function of archipelago species richness, in turn shaped by taxon differences and by the amount and disposition of archipelago area. These results suggest that local-scale (intra-archipelago) processes have a substantial role in determining ISAR form, obscuring the diversity patterns predicted by island theory as a function of archipelago isolation. These findings have implications for the use and interpretation of ISARs as a tool within biogeography, ecology, and conservation.